Ergonomic Assessment of Computer Workstations for Student Employees and Faculty
Members at Saint Louis University School of Public Health
Xue. Liu, Rhoda. Kuziez, Kee-Hean. Ong, Saint Louis University School of Public Health, 3545
Lafayette Ave. St. Louis, MO 63104
Abstract
Objective: To evaluate ergonomic hazards of computer workstations. Methods: This
cross-sectional study consisted of one initial survey (computer workstation components,
ergonomic injury-related symptoms, perceptions of current workstation, and ergonomics
knowledge), work posture measurements, and a follow-up survey to gauge intervention
effectiveness. Results: We recruited 90 participants in this study, whom we divided into two
groups: office and cubicle workers. The top five areas of discomfort complaints were the neck,
shoulders, hands/wrists, upper back, and lower back. We found that both groups underwent
similar experiences of discomfort at their workstations in the past three months; however office
workers endured significantly more chronic discomfort/pain (p=0.018). The office workers
suffered twice as much neck pain as the cubicle workers (p=0.034), perhaps due to an association
between longer working hours at the computer and the frequency of experiencing discomfort
(p=0.043). Furthermore, we found a significant difference between our participants’ actual
working postures in comparison to the neutral/ideal postures (p<0.05). However, no significant
difference existed between groups regarding their mastery of ergonomic knowledge. The
follow-up survey data indicated effectiveness of the intervention: more than 80% of all the
participants agreed they learned more about ergonomics and felt confident to recognize and fix
their ergonomic problems in the future. Conclusions: This study indicates that office and cubicle
workers are both exposed to certain ergonomic hazards and associated health problems. The
intervention targeting people’s knowledge has proven to be effective. In the long-term, it will be
helpful to reduce the risk of ergonomic hazards at computer workstations.
Keywords:
Ergonomics, Computer workstation, Work-related discomfort
Introduction
Millions of employees today conduct their work activities sitting at a desk, behind a
computer for hours on end. With long work shifts, poor workstation set up, and inappropriate
seating postures, ergonomic hazards exist at computer workstations, as demonstrated by multiple
literary sources. 1,2,3 The Occupational Safety and Health Administration (OSHA) defines
ergonomics as “the science of fitting workplace conditions and job demands to the capabilities of
1
the working population.” 4 Ergonomics at a computer workstation involves the presence of
suitable components and accessories and a proper working posture, allowing the employee to
feel physically comfortable to prevent pains that could potentially result.
Each year, thousands of individuals are diagnosed with an illness directly related to
poorly designed workstations, and among these are Musculoskeletal Disorders (MSDs). MSDs
are the repeated trauma and deteriorating of the tissues, joint, tendons, and nerves that affect the
muscles and supporting structures of the body, caused by the work nature or by an employee’s
working environment. 5 The body parts affected are the arms, hands, fingers, neck, back, wrists,
legs, and shoulders; and early warning signs include muscle cramping, stiffness, aching, pain,
and weakness in an area. An example of an MSD is Repetitive Strain Injury (RSI), which refers
to disorders that result from performing a repetitive task, such as typing, writing, or clicking a
mouse. Overall ergonomic disorders are the fastest growing category of work-related illness and
account for thousands of work-related illnesses reported to OSHA, according to the United States
Bureau of Labor Statistics. 6 On the same note, OSHA reports that musculoskeletal disorders in
the United States account for over 600,000 injuries and illnesses that are serious enough to result
in days away from work. 7
A prospective study conducted by Ariens, et al. found that sitting at work for more than
95% of the working time is a risk factor for neck pain, and non-neutral positions are associated
with musculoskeletal symptoms. 8 Another study by Gerr, et al. reported that individuals in
computer workstations have a prevalence of 10-62% musculoskeletal symptoms in their neck
and shoulder region. 9 The treatment for these problems includes the modifications of posture and
the working environment.
Considering ergonomics as a Public Health concern, the aim of this project was thus to
evaluate the ergonomic conditions in the computer workstations at Saint Louis University’s
School of Public Health. This project was conducted as a cross-sectional field study to evaluate
the ergonomic hazards that student employees and faculty members are exposed to in their
computer workstations on the Salus Center’s 3rd and 4th floors. Additionally, this project was
designed to promote ergonomics knowledge and to evaluate the association between the design
of the computer workstations for student employees and faculty members and any pains or
discomforts they may experience. The goal of occupational health is to foster a safe and healthful
work environment, and our aim was see if that goal is realized in our School of Public Health
and to raise ergonomic awareness among our community in the Salus Center.
Methods
Participants were recruited randomly from among the total 150 employees and separated
into two groups: office workers and cubicle workers. This project consisted of five parts.
2
Initial survey
The initial survey completed by the participants included questions on demographics,
physical workstation characteristics, ergonomics injury-related symptoms, perceptions towards
the current working environment, and ergonomics knowledge.
Measurements of linear and postural angles
The measurements were designed to quantify the actual working posture of each individual
employee while at his/her computer workstation. The employee was asked to maintain his/her
usual keying position while measurements were taken using the L510 Lufkin brand 10’
measuring tape and a Fiskars brand protractor. The linear measurement (Figure 1) indicators
included: current seat height from the floor, elbow height from the floor (while seated and
working at the computer), eye height from the floor, and distance between the eyes and the
computer monitor. The specific postural angles measured were the bent angle of the neck relative
to the vertical direction (backward or forward), the twist angle of the neck (left or right) in order
to face the computer, and the lower back angle relative to the thigh and the vertical direction.
Figure 1. Linear and postural angles measurements 10
Informational brochure and follow-up survey
An informational brochure was handed out to every participant as an intervention method
targeting to improve people’s mastery of ergonomics knowledge. One week later, a follow-up
survey was handed out to detect whether there was an increase in ergonomics knowledge, and
the survey was also used to evaluate people’s willingness and competency to fix ergonomic
problems in the future. In general, the follow-up survey was utilized to gauge the intervention
effectiveness.
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Statistical analysis 11
All the data collected from the initial survey, follow-up survey, and field measurements,
were entered into SPSS 18.0 for statistical analysis. Descriptive and frequency analysis were
used to summarize the data distribution, including demographic information, health status,
workload characteristics, and physical workstation characteristics. Chi-Square analysis was
conducted to evaluate the association between the workload characteristics (average working
hour per week, average working hour per day, and average percent of time working at a
computer) and frequency/duration of the discomfort (α=0.05). Additionally, it was used to
figure out whether there exists a significant difference between the two groups for the nominal
variables, including: workload characteristics, physical workstation characteristics, perceptions
towards working environment, and ergonomics knowledge before/after intervention. The
independent t-test was used for the comparison of continuous variables. The one t-test analysis
was used to compare measurements of the actual working postures from our data collection to
the neutral working posture for each specific individual height (α=0.05).10
Results
Demographic characteristics
There are 150 employees working at the School of Public Health, including 75 office
workers and 75 cubicle workers. 90 of them participated in this study and were separated into
two groups according to their workplace, namely as office workers and cubicle workers. The
sample sizes and selected demographic characteristics are shown in Table 1. The average age of
all the participants was 33.9 years (SD, 13.3). The average age for office workers was 42 years
(13.6), and 27(6.4) years for cubicle workers.
Table 1.Demographic Characteristics of Study Population by Sex and Workplace (N=90)
Males
Females
Total
Office
20.0%
26.7%
46.7%
Cubicle
14.4%
38.9%
53.3%
Total
34.4%
65.6%
100.0%
Health status
Of the study population, 18.9% did not feel physically comfortable at their computer
workstation. The data indicated similar results for both groups (p=0.276). The prevalence of
experiencing discomfort in some part of body after working at the computer workstation during
the past 3-months was approximately 57.4% overall. It was 59.5% for the office workers, which
was not significantly higher than the 53.8% for the cubicle workers (p=0.222). Table 2
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represents the Frequency of Experiencing Discomfort among the workers. 23.2% of all
participants reported that they often had uncomfortable feelings in some parts of their body after
working at the computer workstation during the past 3-months; and 46.5% of them sometimes
experienced discomfort. No significant difference (p=0.112) existed between two groups
regarding their frequency of discomfort.
Table 2. Frequency of Experiencing Discomfort (percentage, %)
Often Sometimes
Rarely
Office
Cubicle
14.3%
21.4%
7.2%
8.9%
25.0%
23.2%
Total
23.2%
46.5%
30.4%
Table 3 lists the top five body parts reported to suffer the most discomfort. They were the
neck (37.8%), lower back (35.6%), shoulders (22.2%), hands/wrists (21.1%), and upper back
(13.3%) (Figure 2). The uncomfortable feelings included pain, aching, and burning. The office
workers suffered twice as much neck pain as the cubicle workers (p=0.034).
Table 3. Discomfort at Each Body Part (percentage, %)
Neck
Shoulder
Hand /Wrist
Upper back
Lower back
Office
24.4%
8.9%
7.8%
3.3%
14.4%
Cubicle
13.3%
13.3%
8.9%
10.0%
21.1%
Total
37.8%
22.2%
21.1%
13.3%
35.6%
The percentage distribution of people with different durations of uncomfortable feelings is
shown in Table 4. It varied between the two groups (p=0.018). Approximately 56.3% of all the
participants (Office: 21.8%; cubicle: 34.5%) reported that the symptoms last no more than 2
hours. However, compared with the cubicle workers, the office workers were more likely to
have chronic discomfort/pain (p=0.018)
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Figure 2. Discomfort at Each Body Part 12
Table 4. Distribution of Duration of Discomfort (percentage, %)
<1 hr
1-2hr
3-4hr
5-6hr
7-8hr
1 day
2-3 day
1 month
Cubicle
12.7%
3.7%
9.1%
30.8%
1.8%
3.7%
3.6%
0.0%
3.6%
1.8%
3.6%
14.5%
1.8%
3.7%
5.5%
0.0%
Total
16.4%
39.9%
5.5%
3.6%
5.4%
18.2%
5.5%
5.5%
Office
Work characteristics
Table 5 contains the basic workload characteristics for the two groups. The office workers
spent more time per week (p<0.0001) and per day (p=0.001) working at the computer
workstation than the cubicle workers. However, these two groups spent a similar percent of time
working at the computer (p=0.070), which was approximately 73%. Chi-square analysis found a
significant association between longer working hours at the computer and the frequency of
experiencing discomfort (p=0.043).
Table 5. Workload Characteristics No. (SD)
Average working
hr/week
Average working
hr/day
Average percent of time
working at computer
Office
Cubic
36.0 (1.1)
21.5 (1.0)
7.0 (1.9)
5.0 (1.9)
72.4% (1.5)
73.5% (2.2)
Total
27.9 (1.3)
5.8 (2.1)
72.3% (2.0)
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Physical workstation characteristics
The results of the percentage of participants who had adjustable office equipments (chair and
monitor) in their workplace are shown in Table 6. The percentages for each of our two groups
are similar with regards to the office equipment, except for the chair armrest. 30.6% of chairs
with armrests in the office were adjustable, while only 7.5% in the cubicles were adjustable. A
significant difference has been found (p=0.015).
Table 6. Distribution of Adjustable Workstation Equipment (percentage, %)
Chair
Monitor
Height
Tilt
Armrest
Height
Tilt
Office
41.3%
41.6%
30.6%
34.1%
40.6%
Cubicle
42.2%
25.0%
7.5%
28.6%
40.7%
Total
83.5%
66.6%
38.1%
62.7%
81.3%
Perceptions and behaviors
52.5% of all the participants agreed or somewhat agreed that they were currently exposed to
ergonomic hazards. Both groups had the same attitudes towards their exposure situation
(p=0.207). The data (Table 7) to examine people’s mastery of ergonomic knowledge indicated
that overall only 10.1% of all participants knew a lot about ergonomics, while 25.9% of them
hardly knew anything about ergonomics, and the specific results were similar among groups
(p=0.471). However, around 64.2% of all the participants (office workers: 65.9%, cubic workers:
61.5%) indicated willingness to learn more about ergonomics. Table 8 contains an array of
indicators used to evaluate people’s behaviors related to ergonomic health problems. Only 33.3%
of all the participants often paid attention to their working postures, while 25.6% of them rarely
paid attention. Although a higher percent of the cubicle workers often paid attention to their
working postures, there is no significant difference (p=0.306) between these two groups for the
overall situation. Further evaluation of people’s behaviors indicated that the cubicle workers
were more often likely to twist their neck when they were looking at monitor than the office
workers (p=0.002). But the cubicle workers were more often likely to take a rest when they
experienced discomfort (p=0.035) and take a regular rest regardless of experiencing discomfort
(p<0.0001).
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Table 7. Different Mastery Level of Ergonomics Knowledge (percentage, %)
A lot
Some
A little bit
Hardly any
Office
Cubic
5.6%
4.5%
16.9%
13.5%
14.6%
19.1%
9.0%
16.9%
Total
10.1%
30.3%
33.7%
25.9%
Pay attention to
working posture
Take a rest because of
discomfort
Take a regular rest
Effort to adjust chair
Effort to adjust monitor
Effort to adjust
keyboard
Use mouse supporter
Twist neck while
looking at monitor
Table 8. Evaluation of Behaviors regarding Ergonomic Health Problems (percentage, %)
Often
11.1%
23.3%
5.6%
17.6%
18.7%
15.1%
38.9%
6.7%
Sometimes
20.0%
11.1%
11.1%
19.2%
21.8%
15.1%
11.7%
15.8%
Rarely
15.6%
12.2%
30.0%
25.6%
21.8%
16.5%
11.7%
24.8%
Often
22.2%
24.6%
13.4%
13.7%
12.0%
35.1%
6.3%
16.5%
Sometimes
21.1%
24.6%
12.2%
13.7%
8.6%
18.2%
6.3%
7.7%
Rarely
10.0%
4.1%
27.7%
10.2%
17.1%
0.0%
25.1%
28.5%
Often
33.3%
48.0%
18.9%
31.3%
30.7%
50.2%
45.2%
23.2%
Sometimes
41.1%
35.7%
23.3%
32.9%
30.4%
33.3%
17.9%
23.5%
Rarely
25.6%
16.3%
57.7%
35.8%
39.0%
16.5%
36.8%
53.3%
Frequency
Office
Cubicle
Total
Working posture
The frequency of sitting at each of the following three working postures for the two groups
is shown in Table 9. 47.7% of all the participants often sat at the first neutral working posture. It
was the most common seating posture for both the office and cubicle groups (p=0.156). Second
to that, 37.7% of individuals sat leaning forward; and only 9.3% of people bent backwards while
sitting.
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Table 9. Seating Posture Frequency (percentage, %)
Neutral posture
Leaning forward
Bending backward
Often
Sometimes
Rarely
25.3%
29.9%
6.0%
20.3%
29.0%
11.6%
6.2%
12.2%
41.6%
Often
Cubicle Sometimes
Rarely
22.4%
10.4%
6.0%
17.4%
10.2%
11.6%
3.1%
10.8%
26.2%
Often
47.7%
37.7%
9.3%
Sometimes
Rarely
40.3%
12.0%
39.1%
23.1%
23.0%
67.7%
Office
Total
Table 10 contains the descriptive information on the differences of each working posture
field measurement indicator. This was defined as the difference between the actual measured
value and neutral value of one working posture indicator. The negative values in Table 10
signify that the actual value of one indicator was smaller than the neutral value. It varied for the
thigh angle difference and bent neck angle difference. The negative value indicates the degree of
bending forward either the lower back or neck, while the positive value indicate the degree of
leaning either the lower back or neck backwards. Figure 3 compares the differences in values of
the two groups for each indicator. Most of them are overlapped with each other. According to the
results of independent t-test, there is no significant difference between two groups for the
difference in value of each indicator (p>0.05). However, a significant difference (p<0.05) does
exist between the actual and neutral working posture.
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Table 10. Descriptive Information of Each Working Posture Measurement Indicators
Location
Range
Mean (Std. Deviation)
Δ Seat height
Office
Cubicle
[-1”,6”]
[-2”,6”]
3.13 (1.60)
2.85 (1.55)
Δ Elbow height
Office
Cubicle
[-2”,6”]
[-1”,9”]
3.27 (1.76)
3.70 (2.13)
Δ Eye height
Office
Cubicle
[-7”,4”]
[-7”,3]
2.22 (1.91)
1.75 (1.41)
Δ Distance (eye to monitor)
Office
[-2”,10”]
1.47 (2.55)
Cubicle
[-8”,10”]
1.28 (2.56)
Δ Neck bent angle
Office
Cubicle
[-30o,20o]
[-30o,15o]
11.00 (7.07)
9.75 (8.54)
Δ Neck twist angle
Office
Cubicle
[0o,30o]
[0o,40o]
7.46 (8.08)
9.13 (10.68)
Δ Thigh angle
Office
Cubicle
[-30o,20o]
[-30o,45o]
8.08 (6.82)
11.75 (13.52)
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Follow-up
Table 12 contains the data indicating the effectiveness of the intervention in this study.
Approximately 95% of all the participants agreed or somewhat agreed that they learned more
about ergonomics after reading the ergonomic brochure. Around 85% of them felt confident to
detect the ergonomics hazards in their workplace and fix them. 80% reported they were going to
fix their current ergonomic problems and be more aware of them in the future. The intervention
was equally effective for both groups (p>0.05).
Figure 3. Error Bar of Differences in Values for Working Posture Indicators
(Difference= ABS |Actual value-Neutral value|)
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Table 12. Attitudes toward of Ergonomic post intervention (percentage, %)
Know more
Confident to
Fix ergonomic
about ergonomics
recognize
problems
ergonomic hazards
Office
Cubic
Total
Agree
24.4%
20.9%
18.6%
Somewhat agree
38.3%
36.6%
32.2%
Somewhat disagree
1.7%
6.9%
13.6%
disagree
1.7%
1.7%
1.7%
Agree
13.6%
11.9%
5.1%
Somewhat agree
18.6%
16.9%
25.4%
Somewhat disagree
0.0%
5.1%
3.4%
disagree
1.7%
0.0%
0.0%
Agree
38.0%
32.8%
23.7%
Somewhat agree
56.9%
53.5%
57.6%
Somewhat disagree
1.7%
12.0%
16.9%
disagree
3.4%
1.7%
1.7%
Discussion
Through this project, we were able to evaluate the association between computer
workstation design and ergonomic-related health status of the office and cubicle workers at Saint
Louis University’s School of Public Health. Our data indicates 57% prevalence among all study
participants to have experienced discomfort in some parts of their body after working at a
computer workstation over the past three months. The top five body parts suffering most
discomfort were the neck, shoulders, hands/wrists, upper back, and lower back. According to the
surveys, symptoms usually disappeared within two hours, and thus acute health effects were the
primary concern, although some office workers did have chronic problems. This indicates the
possibility that employees (faculty, staff, and students) working at the School of Public Health
are being exposed to certain ergonomic hazards.
Multiple studies 13,14,15,16,17 have found that ergonomic-related health problems are
associated with: workload characteristics, physical workstation characteristics (office
equipment), perceptions towards ergonomics, and human behaviors. The results of the Workload
Characteristics Analysis indicate that office workers spent significantly more time working at
their computers than the cubicle workers; and the significant relationship between the average
percent of time working at computer with the frequency of experiencing discomfort has been
12
verified in this study. What is worse was that office workers did not take regular breaks as often
as cubicle workers. Therefore, theoretically we could assume that the prevalence of
ergonomic-related health problems for the office workers should be higher than that of the
cubicle workers. However, no significant difference has been found, which can be explained by
multiple reasons. First, in evaluating the adjustability of workstation equipment, we discovered
that 40% of them could be adjusted to meet individual needs for both office and cubicle workers.
Second, both, the office and cubicle workers, were sitting in a posture significantly different
from the neutral posture, thus causing both groups to experience similar discomfort.
Additionally, when we further investigated people’s behaviors regarding ergonomics, we
discovered that only a small number in both groups reported that they often paid attention to their
working postures; and roughly 30-50% of them made efforts to adjust their working environment
to attain physical comfort. It is well known that knowledge, attitudes, and beliefs are
determinants of an individual’s behavior. 18 However, we found that only 10.1% of all
participants stated that they knew a lot about ergonomics.
Therefore, there is a trade-off relationship between each of the assessed factors associated
with ergonomic health problems. In other words, although the prevalence of ergonomic-related
health problems between office and cubicle workers is the same, and both experience discomfort
after working at the computer for some period of time, it is difficult to evaluate exactly what
specific factors are the causes of these similarities between groups.
Fortunately, 64.2% of the study participants expressed their willingness to learn more about
ergonomics, thereby granting effectiveness to our intervention, which targeted people’s
ergonomics knowledge. Due to the limitations of time and money, the simple intervention we
conducted was proven to be effective, as 95% of the study participants agreed or somewhat
agreed they knew more about ergonomics; and 85% of them felt confident to detect the
ergonomic hazards in their workstation and fix them in the future.
The above results also imply some interesting findings. 52.5% of all participants agreed that
they were exposed to some ergonomic hazards. Compared to the cubicle workers, the office
workers had better office equipment that would allow them to develop a healthier working
environment with fewer ergonomic hazards. However, most did not take advantage of this
benefit, and some of those who tried, did so the wrong way, which can be indicated by their
actual working postures.
Because in this study, we evaluated each group, the office workers and cubicles, separately
and together, there are some other explanations to our findings. For instance, in comparison to
the cubicle workers, the office workers were more likely to have chronic health problems. This
could be attributed to the older average age than the cubicle workers, as most of the office
13
workers consist of faculty and staff.
the cubicle workers.
Therefore, the exposure period is longer for them than for
Limitations
This project was designed as a cross-sectional field study, and due to the nature of the study
design, no causative relationship between the ergonomic hazards and ergonomic-related health
problems can be assessed. Ergonomic problems could be associated with multiple factors;
therefore it is difficult for us to detect the specific factors responsible for the discomfort
experienced by employees. To identify the specific culprits causing the pain, we would need to
conduct a controlled experiment and tailor it to individual workstations.
Another limitation may be associated with the working posture evaluation. In evaluating an
individual’s working posture, an array of numbers derived from the 1988 Anthropometric Survey
of the U.S. Army Personnel databases used to define the neutral working position, with which we
compared the actual values measured during this project. In reality, no one can precisely sit in
the neutral posture for an extended period of time. Therefore, our results could overestimate the
problem in relation to the ergonomic-pains resulting from working postures. An operational
range of values for each working posture indicator should be developed in future studies.
The intervention we provided was the same for all the participants. It might be more
effective if we could tailor the intervention to fit each individual’s specific knowledge level of
ergonomics, as some participants may not have read the brochure carefully if they already had
some ergonomic knowledge. If this is the case, they might have responded that the brochure did
not help them learn more.
Some individuals indicated in the post-intervention survey that they do not feel strongly
about changing the ergonomic hazards in their computer workstations. However, a number of
these individuals made point to personally explain this response was due to the fact that they do
not have the resources to make the necessary changes.
Finally, computer workstations vary in characteristics and components. Because of these
differences, the generalization of our study is limited to only similar workstations.
Conclusions
This study and our findings confirm that employees working in the computer workstations at
Saint Louis University’s School of Public Health are exposed to some ergonomic hazards, which
are associated with multiple factors. Although no specific causative relationship has been
verified, the results provide us with a general picture about the current exposure situation and
some health problems of concern at the Salus Center. This could be a beneficial panel study for
any further future investigations looking at health-related ergonomic problems in our university.
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Acknowledgements
We appreciate the help of Brett Emo and Jason Kennedy pilot testing our survey
questionnaires; Kevin Stillman for permission to conduct this study in the Salus Center and
printing of our ergonomic brochures free of charge. Finally, we would love to thank everyone
who participated in this project and made it possible.
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